Internal-combustion engine



June 7, 1927. 1,631,702

E. SOKAL INTERNAL COMBUSTI 0N ENGINE Filed July 9, 1925 INVENTDR. {W MW BY W y ATTORNEYS.

, EDWARD 80m, OF BROOKLYN,

PORATIOH, OF BROOKLYN NEW Y0 Patented June 7, 1927.

UNITED STATES NEW YORK, ASSIGNOB T0 AIIEBICAN KATALI'IE 00B- BK, A GOBPOBL'I'ION OF DELAWARE.

INTERNAL-COMBUSTION ENGINE.

Application filed July 9, 1925, Serial 80.

This invention relates to internal combustion engines, and more particularly to engines of the relatively high compression t e.

it is an object of the invention to provide within the combustion chamber of such an engine, substantially stable chemical means possessing the property of counteracting the phenomena and disadvantageous results of detonation, or knocking, which means may be referred to as a detonation counteractant.

Another object of the invention is to provide a beneficial material for location within a combustion chamber which. possessing the property of decreasing the tendency to carbon deposition and heat loss, enhances the efficiency of engine operation.

A further object of the invention is o provide a coating material for the purposes recited, among others. and which may be readily disposed within the interior of a combustion chamber and the effective pro erties of which will not be permanently a ected by the conditions within the combustion chamber.

This application is in part a continuatlon of my co-peuding application for improvements in internal combustion engines filed April :21, 19:25, Serial No. 24.882.

At the present time the phenomenon of detonation, or knocking, during the operation of internal combustion engines is of much interest because. other conditions being equal, it is more pronounced with engines of high compression ratios. Accordingly this tendency to detonate with a given fuel becomes practically a limiting factor for improvement in the thermal efliciency and power output through an lncrcase 1n the compression ratio. TlllS is particularly the case with the 'constant volume cycle type of engine which is used almost exclusively in automobiles and in aeroplanes and also to a considerable extent in small marine and stationary engines.

It is trite that there are other limiting factors. such as loss in mechanical efliciency. which may ofi'set the gain in thermal ef ficiency after a certain increase in the compression ratio. but the limitation due to the injurious effects of detonation becomes operative before these other limiting factors exert their influence. In order to obviate or decrease detonation. it has been suggested that various materials be added to the fuel.

48,583, and in Grel-t Britain Kay 11, 1925.

Some of these appear to have a favorable action butshow the interesting characteristic that if they are added to the fuel in excess of very small quantities, they cause a decretase rather than an increase in power outpu Various tentative explanations have been offered for the phenomenon of detonation. It is my view that detonation, or knocking in internal combustion engines is mainly due to a decomposition or breaking down of the unburned fuel, or in other words, to the dis sociation of the larger molecules of the fuel under the influence of heat and pressure into a greater number of smaller molecules whereby there is caused a sudden rise of pressure. This rise of pressure may not be indicative of the true ressure condition within the whole body of the fuelair mixture, but is rather in the nature of a localized impact. This view is supported by the following considerations: First. the detonating tendency of various fuels is practically a function of their thermal stability, for example. the tendency to detonate decreases in the following order: kerosene, ordinary gasoline, aromatic gasoline, benzol, alcohol and hydrogen, and the thermal stability increases in the same order; second, the indicator diagram of detonating engines shows a very rapid rise of pressure which lasts only a very short period of time, is followed by an equally rapid decline, frequently occurs several times at the beginning of the expansion stroke. the peaks becoming smaller each time, and these rises of pressure are of such short duration that the corresponding pressure volume area is too small to represent an appreciable amount of useful work and hence'they manifest themselves as de structive impactsrthird, detonation is accompanied by lost power. deposition of carbon and great loss of heat to the water jacket. which loss'of power and deposition of carbon may be considered natural results from the decomposition of the fuel, and the loss of heat to the water jacket is probably due to radiation caused by glowing particles of carbon and to the impacts: and. fourth. it has been shown that various factors which cause an increase in the rapidity of combustion and make the combustion more complete have a rather pronounced efi'ect in counteracting detonation. This would seem to follow as an indirect result of the fact that the lUS Ill]

molecules of the fuel cannot simultaneously undergo a reaction of combustion and of decomposition.

I have discovered that detonation may be counteracted directly and without accelerating combustion by fixedly disposing in the combustion chamber of a standard internal combustion engine a coating material containing a substance, or substances, which has a low melting point, or which passes into another form at a relatively low temperature. Detonation being due to a thermal decomposition of the fuel, then by bringing the fuel-air mixture into contact with a det onation counteractant, the decomposition may be inhibited either by lowering the temperature of the unburned fuel; by catalyzing negatively the reaction of decomposition, or it may be by the prevention of a positive catalytic effect on the reaction of decomposition by the walls of the combustion chamber. It may be that these effects are combined and in the present state of knowledge, it would be very difficult, if not impossible, to separate them quantitatively.

\Vhile it is believed that the effect produced is primarily a thermal skin effect, resulting from a cooling of the fuel-air mixture by a low melting substance or a substance which acts endothermically Without melting, as, for example, the formation of an allotropic substance, it is to be considered that the effect may be enhanced or diminished by other characteristics such as conductivity, catalytic properties, reactivity, with particular reference to capability of reaction with oxygen and other components of the gaseous mixture, etc. It must furthermore be borne in mind that such a thermal molecular skin efl'ect of the coating resulting in a cooling down of the unburned fuel an a counteracting of its decomposition, may also influence the rapidity of combustion, and likewise any negative catalytic effect on the decomposition reaction may be combined with a negative catalytic effect on the combustion. However, such characteristics are probably purely accidental coincidences and are not fundamentally of concern in connection with my invention, in accordance with which detonation may be counteracted by fixedly disposing within the combustion chamber of an internal combustion engine a properly adapted permanent solid substance.

It was expected and confirmed by experiments that an extreme cooling effect on the fuel-air mixture would interfere with the functioning of the engine if not render it entirely inoperative, while the same effect, if utilized to a much smaller degree, would result in counteracting detonation without any functional interference.

In practice the invention comprises the utilization of a coating material within a combustion chamber containing a substance of low melting point, as a low melting metallic substance, such as lead, antimony and tellurium. The substance of low melting point may be applied alone in a finely divided condition, as, for example, by brushing the same on a desired surface within the combustion chamber. When a metal is used, it may be applied to the cylinder head through the use of the Schoop metal spraying process. By this latter method the coating is caused to enter into the pores of the cylinder head where it is securely held and not subject to substantial reaction with the constituents of the gaseous mixture. Further, the coating material ma comprise a low melting or endothermically reactive constituent in admixture with a suitable binder, for example, the coating material may consist of subdivided lead and a silicate binder. The proportions of active substance to binder may be varied according to requirements, and it has been found that a satisfactory result is produced when a mixture containing one-half ounce of subdivided lead to one ounce of'a silicate is employed. Application may be accomplished by cleaning the desired surface area, coating such area with the detonation counteractant and baking or setting. This procedure may then be repeated until the desirednumber of coats has been applied. The active substance in the mixture, even though melted, is firmly retained, does not detach itself, and is so intimately in contact with the binding material, and in some cases chemical combination may actually take place, that its reactivity with the gaseous mixture is reduced to a minimum.

The amount of detonation counteractant to be applied in a particular type of engine may be readily determined by suitable tests indicating the proper surface area to be coated in order to obtain eflicient operation.

The detonation counteractant is fixedly disposed within the combustion chamber and its disposition is susceptible of being accomplished in a variety of ways. Its relative location within the combustion chamber may also be chosen as desired. For example, the counteractant may be applied to the to of the piston, or directly to the cylinder wall, if this wall is part of the combustion chamber, or to the cylinder head. In certain instances its exposure to the fuel-air mixture may be regulated when desired.

Utilization of 'a detonation counteractant on account of its endothermic properties produces a marked cooling effect on the fuel-air mixture, so that decomposition of the unburned part is retarded if not prevented. In other words, it prevents the unburned particles in the flame from reaching a temperature sufliciently high to cause their decomposition before actual ignition. If this efi'ect were to be availed of to itsfullest extent, it would'also revent propagation of the flame, and accor ly proper functioning of an e e. An experiment in which a large'part of the surface of a cylinder head was covered with an active substance alone in a finely subdivided condition, illustrated the correctness of the foregoing statement in that it rendered the engine inoperative. This experiment speaks rather against an explanation by catalytic action. It is necessary therefore to apply the active substance as a coating material to only a portion of the interior of the combustion chamber or if it is desired to cover a larger area, this active substance is to be attenuated through admixture with a binder which is inert.

From the foregoing, it will be seen that the effectiveness of the detonation counteractant contem lated by the invention maybe due to the act that the material employed possesses the ability of undergoing a heat-absorbing change during those periods of engine operation wherein the temperature within the combustion chamber is the highest and the tendency toward detonation is greatest. Moreover, since the invention is directed to the use of a permanent detonation counteractant, the material used should. be such that it is capable of returning to its ori al condition during interme ate peri s of engine operation. Accordingly, the term endothermically reactive material, as employed in the appended claims, is intended to include all materials capable of undergoing, at least in the exposed layer thereof, at the temperatures and under theconditions existent within the chamber in the internal combustion engine in which it is employed, any reversible chan of such nature that heat will be absorbe and the required cooling effect exerted at the hi her range of the temperatures within the chamber, and that the material will tend to return to its original condition (with a co uent release of heat) at the lower range 0 temperatures within the chamber. Furthermore, the term low-melting substance, as used in the claims is intended to refer to a material whose melting point is such that it is capable of under ing a reversible change in state between 5:; hlgher and lower ranges of temperatures, and under the conditions, in the chamber in which it isused.

Accordin l the term low melting substance capai e of undergoing a reversible change in state under engine operating conditions is intended to exclude materials of extremely low melting point such as tin and bismuth as well as materials having a relatively high melting point, such as iron and nickel.

I have shown b a series of experiments made under actu road conditions with a special high compression Ford cylinder head which was used on the one hand without ap lication of a detonation counteractant an on the other, with the application of a detonation counteractant that under heavy load conditions, as for example, hill climbing, the uncoated head detonated at practically all spark and throttle positions, while with the cylinder head coated, the engine operated without detonation with a wide open throttle and a fairly advanced spark. These tests were repeated and varied many times and the results were concordant and satisfactory, evidencing an increase in power output and a counteracting of the conditions to which detonation is due, from which it follows that the thermal efliciency may be increased b an increase in the compression ratio wit out the attendant disadvanta es of detonation.

be drawing is a partly sectional view exemplifying a form of the invention wherein a permanent detonation counteractant, such as contemplated by the invention, is fixedly disposed within the combustion chamber of an internal combustion engine in the form of a coating applied to the exposed surfaces of the piston head and the exhaust valve, the hottest points on the walls of the chamber.

In this exemplification, a cylinder block 1, together with a high compression cylinder head 2 provides a combustion chamber 3 into which the contacts 4 of a spark plug 5 extend. A portion of the wall of the combustion chamber is provided by the piston head 6 on the surface of which is a coating 7 contaming a permanent detonation counteractant, such as lead. Another rtion of the wall of this chamber is provi ed by the sur face of an exhaust valve 8 on which there may also be provided a coating 9, which may also contain lead, for example.

The detonation counteractant preferabl comprises a substance or substances whic are nonabrasive, and accordingly no injury to the cylinder walls will result in the event that a portion should become detached.

Among the advantages arising through the utilization of the detonation counteractant, mention may be made of the following:

lack of detonation or knocking, lower fuelconsumption, more flexible operation of the engine, decrease in carbon deposition and an ly in connection with the use of high compression engines.

It is to be understood that the invention I mi increase in the thermal efiiciency, particularin its broad sense is for the employment in y the combustion chamber of an internal combustion en ine of a material possessing the permit the tion includes the use of that generaL-class of substances which are capable of beneficially undergoing a heat-absorbing change under the conditions of engine 0 eration, and that it is not intended to meludie any mate rial possessing alone or also another quality which would act to offset the advantage of reducing detonation as contemplated by this invention.

While the theory herein presented offers a basis for an understanding of the manner in which the detonation counteractant may function, and while it is supported by known facts, it is to be understood, of course, that the operativeness and racticability of the invention is not depen ent upon or limited in any way by the correctness of such theory.

Since certain changes may be made in the detonation counteractant above described and different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the eneric and specific features of the invention herein described, and all statements of the scope of the invention] which, as a matter of language, might be said to fall therebetween.

Having described my invention, what I claim as new and desire'to secure by Letters Patent is:

1. In an internal combustion engine, the combination with a combustion chamber, of a relatively per ent detonation counter actant fixedly di s zo sed therein, said detonation counteractant comprising a material which acts endothermically to absorb heat during those periods of engine operation when the temperature within the chamber is the greatest, and which is capable of releasing eat during intermediate periods of engine operation.

2. In an internal combustion engine, the combination with a combustion chamber of a material, fixedly dis osed within said chamber, which is endot ermically reactive under engine operating conditions.

3. In an internal combustion engine, the

- combination of a combustion chamber, a perwith intake and exhaust valves and ignition means, and a permanent detonation counteractant fixedly dis osed within said combustion chamber, sai detonation counteractant comprising a low melting substance, capable .of undergoing a reversible change 1n state under engine operating conditions.

4. In an internal combustion engine, the combination of a combustion chamber, a permanent detonation counteractant fixedly disposed within said combustion chamber, said tonation' counteractant including a low meltin substance capable of undergoing a reversi le change in state under engine operating conditions, and a binder.

5. In an internal combustion engine, the combination of a combustion chamber, a permanent detonation counteractant fixedly disposed within said combustion chamber, said detonation counteractant comprising a low melting substance capable of undergoing a reversible change in state under engine operating conditions, and a silicate.

6. In an internal combustion engine, the combination of a combustion chamber, and a permanent detonation counteractant fixedly disposed within said combustion chamber, said detonation counteractant comprising a low melting metallic substance capable of undergoing a reversible change in state under engine operating conditions.

7. In an internal combustion engine, the combination of a combustion chamber, a permanent detonation oounteractant fixedly dis osed within said combustion chamber, sai detonation counteractant comprising lead, and a binder.

8. In an internal combustion engine, the combinaton of a combuston chamber, a permanent detonation counteractant fixedly disposed within said combustion chamber, said detonation counteractant comprising lead in a finely divided condition, and a silicate binder.

9. As an article of manufacture, a coating material for use within the combustion chamber of an internal combustion engine, comprising a low meltin substance capable of undergoing a reversible change in state under engine operating conditions and of counteracting etonation and a silicate binder.

'10. As an article of manufacture, a coating material for use within the combustion chamber of an internal combustion engine, com risin a low melting metallic substance capa le 0 undergoing a reversible change in state under engine operatin conditions and of counteracting detonation and a binder.

11. As an article of'manufacture, a coating material for use within the combustion chamber of an internal combustion engine, comprising finelysubdivided lead and a silicate. o

12. As an article of manufacture, a coating material for use in a. combustion chamber of an internal combustion engine comprising a material which is endothermically reactive under engine operating conditions admixed with a binder.

13. A method of efi'ectin improvement in the operation "of interna combustion engmes, which comprises permanently exposing withm the combustion chamber thereof a material which is endothermically reactive under engme operating conditions.

lilfu III) 14. A method of effecting improvement in the operation of internal combustion en es, which comprises permanently exposing within the combustion chamber thereof a low melting substance. capable of undergoing a reversible change in state under engine operating conditions.

15. A method of eifecting improvement in the operation of internal combustion engines, which comprises counteracting detonation of the successive fuel charges in the combustion chamber of an engine by permanently exposing to such charges a solid material which is endothermically reactive under engine operatin conditions.

16. In an internal combustion en ine, the combination of a combustion cham er having a compression ratio which under normal conditions of operation would result in detonation, or knocking, and a permanent detonation counteractant fixed disposed in said combustion chamber, said detonation counteractant comprising a material which is endothermically reactive under engine opcrating conditions.

17. In an'lnternal combustion engine, the combination with a combustion chamber of a material fixedly disposed therein and capable of undergoing a reversible physical heat absorbing change under the temperature conditions present in the engine during operation.

18. In an internal combustion engine, the combination with a combustion chamber of a material which is endothermically reactive under engine operatin conditions fixedly disposed on certain o of the walls of the chamber which are hottest during operation.

19. In an internal combustion engine, a combustion chamber arranged for the reception of a gaseous mixture and fitted with a piston presenting an exposed suriace to the gases in said chamber, prising a coating containing a low melting substance capab e of undergoing a reversible change in state under engine operating conditions.

20. In an internal combustion engine, the combination with a combustion chamber of a coating permanently aflixed to certain of the walls of said chamber, said coating containing metallic lead.

In testimony whereof I afiix my signature.

EDWARD SOKAL.

said surface com-v those portions 14. A method of effecting improvement in the operation of internal combustion en gines, which comprises permanently exposing Within the combustion chamber thereof a low melting substance capable of undergoing a reversible change in state under engine operating conditions.

15. A method of effecting improvement in the operation of internal combustion engines, which comprises counteracting detonation of the successive fuel charges in the combustion chamber of an engine by permanently exposing to such charges a solid material which is endothermically reactive under engine operating conditions.

16. In an internal combustion engine, the combination of a combustion chamber having a compression ratio which under normal conditions of operation would result in detonation, or knocking, and a permanent detonation counteractant fixed disposed in said combustion chamber, said detonation counteractant comprising a material which is endothermically reactive under engine operating conditions.

17 In an'internal combustion engine, the combination With a combustion chamber of a material fixedly disposed therein and capable of undergoing a reversible physical heat absorbing change under the temperature conditions present in the engine during operation.

18. In an internal combustion engine, the combination with a combustion chamber of a material which is endothermically reactive under engine operating conditions fixedly disposed on certain of those portions of the walls of the chamber which are hottest during operation.

19. In an internal combustion engine, a combustion chamber arranged for the reception of a gaseous mixture and fitted with a piston presenting an exposed surface to the gases in said chamber, said surface comprising a coating containing a low melting substance capable of undergoing a reversible change in state under engine operating conditions.

20. In an internal combustion engine, the combination with a combustion chamber of a coating permanently atlixed to certain of the Walls of said chamber, said coating containing metallic lead.

In testimony whereof I affix my signature.

EDWARD SOKAL.

Certificate of Correction.

Patent No. 1,631,702.

Granted June 7, 1927, to

EDWARD SOKAL.

It is hereby certified that error appears in the printed specification of the abovenumbered patent requiring correctlon as follows: Page 4, line 53, claim 3, strike out the WOIdS a per and insert instead the word fitted; pa e 5, line 21, claim 16,

for the word fixed read fixedly; and that the said Letters atent should be read with these corrections therein that the same may conform to the record of the case in the Patent Oifice.

Signed and sealed this 19th day of July, A. D. 1927.

[scan] M. J. MOORE, Acting Commissioner of Patents.

Certificate of Correction.

Patent No. 1,631,702. Granted June 7, 1927, to EDWARD SOKAL.

It is hereby certified that error appears in the printed specification of the above numbered petent requiring correction as follows: Page 4, line 53, claim 3, strike out the WOIdS a per and insert instead the word fitted; pa e 5, line 21, claim 16, for the word fixed read fixedly, and that the said LetterS atent should be read with these corrections therein that the same may co'nform to the record of the case in the Patent Oflice.

Signed and sealed this 19th day of July, A. D. 1927.

[SEAL] M. J. MOORE,

Acting Commzrissimwr of Patents. 

